1. What causes ocean waves?

2. Ocean Waves Ocean waves are caused by wind.
The air drags across the surface of the water and passes energy, causing waves

3. Tsunami
What causes a Tsunami?

4. Tsunami
A tsunami is caused by earthquakes, land slides and underwater volcanoes.

5. Tsunami warning
There are many buoys placed in the oceans to detect a rise in wave height.
Seismographs detect earthquakes.
If a seismograph detects seismic activity underwater a Tsunami warning is sent out

6. Wave Parts Crest – the high point of the wave.
Trough – the low point of the wave
Wave height – the distance between the crest and the trough.
Wavelength – the distance between one wave crest and the next wave crest or one trough and the next trough.

7. Wave Parts

8. Breakers Wave bottom begins to drag on sea floor.
Bottom of wave slows down.
Top of wave continues at same speed.
Wave height grows.
Wave falls over

9. Longshore Current Where waves meet land at an angle.
Causes current parallel to the shore.
Causes the beach sand to move down the shore. ( longshore drift)

10. Rip Currents
Occur where streams of water break through sandbars and drain rapidly back into the ocean.
Occurs where wind pushes water back from shore.

11. Quiz 1. A wave is moving a) Sand b) Water c) Energy d) Air
2.Surface waves are caused by   a) Fish  b) Wind   c) Boats   d) Earthquakes

12. Quiz
3.  Waves that begin underwater may be caused by  a)  Fish   b) Earthquakes   c) Wind   d) Boats
4.  A wave that falls over and forms white caps is called   a) Breaker   b) Surfer   c) Tsunami   d) None of the above

13. Quiz
5. A buoy is something that  a) Lives underwater  b) Sinks c) Measures waves  d ) Floats
6.  What does the word "marine" mean in the phrase "marine creatures?"   a) Blue  b)  Animals that live near the water  c)  A branch of the armed forces   d) Animals that live in the water

14. Quiz 7. Name the two main types of waves.
8.  What do you think scientists will have to learn more about before they can predict a tsunami?